The porcine rota-like virus and porcine calici-like virus will be further characterized biochemically and antigenically. Techniques will be developed for the detection of these viruses and the antibodies directed against them, and the pathogenesis of these viral infections will be studied in gnotobiotic pigs. Studies on the active and passive immune response of swine to TGE virus and rota-virus will be confirmed and the effects of varying the routes of virus inoculation on the level of passive immunity provided by the sow to the suckling pigs will be evaluated. Assays for the detection of rotaviruses and antibody to rotaviruses will be further developed and refined. A simplified procedure for extracting rotaviral double-stranded RNA will be further developed to permit the extraction of smaller quantities of virus-laden samples. Porcine and bovine rotaviruses recovered from different herds will be compared by electrophoretic analysis of their RNA's in polyacrylamide gels.